Sheet carrier cylinder for use in a polychrome rotary printing press adapted for both one-side and two-side printing

ABSTRACT

Sheet guide or transfer cylinder for use in a polychrome rotary printing machine adapted for one-side or two-side printing, in which the sheet printed in the first printing device is pressed against the solid jacketed surface of the printing cylinder at the point of tangent, i.e., at the point of contact between the sheet guide or transfer cylinder and the printing cylinder arranged before it, in the direction of movement, by directing and carrier elements arranged on the sheet guide or transfer cylinder, and is securely carried thereby until the suction means disposed on the sheet guide or transfer cylinder grasp the end of the sheet and lift it off from the cylinder. The directing and carrier elements are arranged on the periphery of the sheet guide or transfer cylinder so as to be radially movable, whereby they permit crease-free transfer of the sheet to a further printing device.

United States Patent Rudolph et al.

1 3,654,861 [451 Apr. 11,1972

[72] Inventors: Otfried Rudolph, Dresden; Wilfried Kuhn,

Radebeul, both of Germany [73] Assignee: Veb DruckmaschinenwerkRadebeul, Germany 22 Filed: Apr. 6, 1970 21 Appl.N0.: 25,765

Planeta,

[52] U.S.Cl ..101/183, 101/230, 101/409 [51] Int. Cl ..B4lf 7/06,B4lf2l/06 [58] Field of Search... ....101/230, 246, 420, 409-412,

l01/l83-l84,136,137,140,141,142,144,145;

2,965,026 12/1960 Woodward 101/420 FOREIGN PATENTS OR APPLlCATlONS960,900 4/1950 France ..101/246 Primary Examiner-J. Reed FisherAttorney-Nolte and Nolte [57] ABSTRACT Sheet guide or transfer cylinderfor use in a polychrome rotary printing machine adapted for one-side ortwo-side printing, in which the sheet printed in the first printingdevice is pressed against the solid jacketed surface of the printingcylinder at the point of tangent, i.e., at the point of contact betweenthe sheet guide or transfer cylinder and the printing cylinder arrangedbefore it, in the direction of movement, by directing and carrierelements arranged on the sheet guide or transfer cylinder, and issecurely carried thereby until the suction means disposed on the sheetguide or transfer cylinder grasp the end of the sheet and lift it offfrom the cylinder. The directing and carrier elements are arranged onthe periphery of the sheet guide or transfer cylinder so as to beradially movable, whereby they permit crease-free transfer of the sheetto a further printing device.

4 Claims, 10 Drawing Figures PATENTEUAPR 1 1 1912 sum 1 OF 5 FIG].

INVENTORS ATTORNEY PATENTEDAPR 1 1 1912 3 654, 8 61 sum 3 BF 5 w/z FP/[Dx u'k/A/ INVENTOR'S ATTORNEY In order to assure the transfer of a sheetupon a change in the size of the sheets it has been proposed to fix thegripper opening point for the release of the sheet printed in the firstprinting device at the leading edge'of the sheet in a uniform mannersuitable for all of the formats to be printed on the machine. Until thetime when the trailing edge is grasped by the suction means disposed onthe sheet guide or transfer cylinder, it is pressed against the solidperipheral surface of the printing cylinder by pressure strips which arealso arranged on the sheet guide or transfer too and in this manner thesheet is securely guided. In both area of the gripper opening point,suction devices are provided which are directed against the printingcylinder, and which, in the case of intermittent operation, hold thesheets already released by the grippers. The flexible pressure stripswhich are arranged on the sheet guide or transfer cylinder, are in thisarrangement mounted on segments which are displaceable, i.e., movable,circumferentially and axially.

This particular sheet guide or transfer cylinder has the disadvantage inthat pressure is applied to the sheet also at the transfer point andnamely to the point of contact between the sheet guide or transfercylinder and the second printing cylinder, by the flexible pressurestrips provided on the sheet guide or transfer cylinder. This isparticularly disadvantageous in connection with the printing of thispaper using high machine speeds, as the time interval between thetransfer of the sheet at the transfer point and its arrival at thesecond printing zone, i.e., the time interval between the printingcylinder and the rubber cylinder or roller, is to short for settling;the fluttering or movement of the sheet too in the direction of itsmovement and crosswise thereto, which fluttering movement is produced bythe reversal, i.e., turning of the sheet to be eliminated. The pressureapplied while the sheet is undergoing fluttering movements results inthe formation of creases in the sheet.

It is an object of the invention to provide a sheet guide transfercylinder which will result in a superior handling of the sheet even athigh printing speeds and for all of the different materialsthat are tobe printed.

A further object of the invention is to provide a sheet guide ortransfer cylinder for one-side and two-side printing which assures acrease-free transfer of the sheets from the sheet guide or transfercylinder to the next succeeding cylinder in thedirection of movement.

These and other objects and advantages of the invention are obtainedbyproviding on the periphery of a transfer cylinder carrier elementswhich will press the sheet at the point of contact therewith against theouter surface of the preceding cylinder. The carrier elements aremovable in a radial direction. The-radial movement of the carrierelements is controlled by a parallel rocker arrangement which inducesthe movement of the carrier elements at the point of contact in thedirectionfrom the periphery in toward the interior of the transfercylinder.

The invention will be understood from the following description withreference to the-drawings accompanying this application of an embodimentof the invention, in which:

FIG'. 1 is a general, schematic representation of said embodiment;

FIGS: 2 to 7 are details thereof, shown in various positions;

FIG. .8 is a detail view drawn on a larger scale, partly in sectionalong lines C C in FIG. 9, to show the transfer cylinder mechanism inaccordance with the invention;

FIG. 9 is a sectional side elevation of the transfer cylinder takenalong line A-A of FIG. 8; and

FIG. 10 is a sectional front elevation of the transfer cylinder takenalong. line B -B of FIG. 9.

Referring to the drawings and in particular to the printing assembly asshown in FIG. 1, the sheet fed by the feeding drum 6 to the printingcylinder 1 is being printed at the zone of contact between the printingcylinder 1 and the rubber cylinder 2. In the case where the sheet is tobe printed on one side only, the sheet is, upon further rotation of thecylinder, siezed by the grippers arranged in the transfer cylinder andis fed with its leading edge in front, to the printing cylinder 4. Inthe contact zone established between the printing cylinder 4 and therubber cylinder 5, the sheet is printed on the same side with a secondcolor. Thereafter the sheet is fed to a further printing I unit or to areceiving station. If, however, the machine is set for printing on bothsides of the sheet, the sheet which has been printed in the contact zonebetween printing cylinder 1 and delete rubber cylinder 2 is retained onthe printing cylinder 1 until the trailing edge of the sheet has reachedthe contact point between the printing cylinder and the transfercylinder (r At this point (FIG. 2), the trailing edge of the sheet issiezed by the suction devices 7 arranged on the sheet transfer cylinder3. On the further rotation of the cylinder (FIGS. 4, 5), the suctiondevices 7 and the associated gripper 8 are retracted into the spaceinside the cylinder and the trailing edge of the sheet transferred fromthe suction device 7 to the gripper 8. Upon completion of the transferof the trailing edge (FIGS. 6, 7), the gripper 8 and the suction device7 are moved to their outside position and the sheet now with itstrailing edge in front istumed over without creasing and fed to theprinting cylinder 4 of the next printing unit.

In the zone of contact between the printing cylinder 4 and the rubbercylinder 5, the sheet is printed on its reverse side.

In the printing assembly shown in FIG. 8, a sheet 9 which is on theprinting cylinder 1 and which has been printed by the first printingunit is guided on the cylinder 1 past the tangent point thereof. Whilethis is done, all the way to the trailing edge of the sheet 9, the sheet9 is pressed against the solid outer surface of the printing cylinder 1and is securely held by carrier elements 10 which are arranged on thetransfer cylinder 3 and are provided with resilient strips 11. At itsleading edge, the sheet 9 is held by a gripper system arranged on theprinting cylinder 1; this is done up to the gripper opening point. Thegripper opening point is identical for all of the formats thatare to beprinted in the machine and is determined by the smallest possible (FIG.3). A longer sheet 9 (FIG. 2) which has already been released by thegripper system arranged on cylinder 1 is securely carried only by thecarrier elements 10 (FIG. 8). When the trailing edge of the sheet is atthe tangent point, it is siezed by a suction device 7 provided on thesheet guide or transfer cylinder 3 and removed from the printingcylinder 1.

Upon further rotation of the cylinder, the transfer of the sheet, whichhas been printed on by printing cylinder 1, to the printing cylinder 4is achieved in the manner as has been described above and as illustratedin FIG. 2-7.

According to the invention, a crease free transfer between the sheetguide or transfer cylinder 3 and the printing cylinder 4-is achieved bythe fact that the carrier elements 10 with resilient strips 11 arecarried past the printing cylinder 4 without contacting it. The sheet 9siezed by the gripper system of the printing cylinder 4 (FIG. 7) thuscan settle down from the flutter or movement thereof caused by itsinversion or reversal (FIGS. 4, 5, 6) before it undergoes printing inthe second printing unit. The advancement of the carrier segment 10,opposite printing cylinder 1, and its retraction opposite printingcylinder 4 is carried out by a parallel rocker system, which will now bedescribed with reference to FIGS. 8 10.

On the lateral wall of the printing machine, there is provided a cam 23(FIG. 10) on whose surface a roller 24 rolls, which roller is mounted ona roller lever arm 26 by means of a rocker spindle 25. Roller 24 isbiased on a surface of cam 23 by a spring 22 disposed on lever arm 26.In the end walls of the sheet guide or transfer cylinder 3, there ismounted a rocker shaft 15 (FIG. 9). As an extension of the rocker shaft15 the spindle 25 of lever arm 26 is provided for motion with thisshaft. The circular eccentrics 14 are provided on their interiors with agroove in which a sliding spring 18 is disposed which in turn is affixedto the circular eccentric by means of a screw 17. The rocker shaft 15has been provided with a longitudinal groove 19in which the slidingspring 18 is guided. The circular eccentrics 14 are thus displaceable oradjustable axially on the rocker shaft 15 and can be locked in anyposition by a screw 20 disposed in the sliding spring 18.

In the end walls of the sheet guide or transfer cylinder 3 (FIG. 8),there is mounted parallel to the rocker shaft 15 a rocker shaft 16.Circular eccentrics 14 are displaceably, i.e., adjustably arranged onthis rocker shaft in the same manner as described for the circulareccentrics of the rocker shaft 15. On each circular eccentric 14 of therocker shafts l and 16 there is rotatably, i.e., adjustably mounted ablock 13 which block is fixed by means of flange plates 21 mountedthereon in its axial position in relation to the circular eccentric 14.Each block 13 on the rocker shaft 15 is joined to a block 13 disposed onrocker shaft 16, by means of carrier element 10. On the rocker shafts15, 16 there are also provided levers 17 and 31, respectively, theselevers being interconnected by means of a link 29 attached to them bypins 28 and 30, respectively.

The drive lever 27, the link 29 and the driven lever 31 form a parallelrocker arrangement which assures positive drive when the circulareccentrics 14 are moved out of their extended position. in theembodiment shown, the circular eccentrics 14 which are associated withthe rocker shaft 15 and 16 are in their extended position when thecarrier elements are in their inner position. This structuralarrangement has the advantage in that it permits a maximum movement ofthe carrier elements 10 in the radial direction.

For adjustment of the pressure between the resilient strips 11 arrangedon the carrier segments 10 and the peripheral surface of the printingcylinder 1, elongated openings 13A are provided which extend radially inblocks 13. The adjustment of the pressure is carried out by looseningscrews 12 in these openings and shifting the carrier elements 10radially, either towards the interior of the sheet guide or transfercylinder 3 or towards the printing cylinder 1, until the desiredpressure is obtained. Then the screws 12 are retightened.

The change over of the sheet transfer carrier cylinder 3 for one-sideprinting is carried out by locking the carrier elements 10 in the innerposition, in which the roller 24 on roller lever 26 is located at thehighest point of cam 23 (FIG. 10).

The roller lever 26 is provided with a cross-slotted indexing means 32.When the spring-loaded indexing pin 33 is drawn outwardly and turned, itsnaps into an opening 34 in the sheet guide or transfer cylinder 3, thuslocking the carrier elements 10 in their inner position against thepressure of spring 22.

The sheet or transfer cylinder 3 is converted from one-side to two-sideprinting by removing the indexing pin 33 from the opening 34 in theconventional manner. Thereafter, the roller 24 is urged against the camsurface by roller lever 26 under the force of spring 22, so that whenthe cylinder rotates, the guide elements 10 are moved into thecorresponding radial position by the cam 23. I

We claim:

l. A printing machine comprising a sheet transfer cylinder, meansincluding at least one first printing cylinder ahead of said transfercylinder and at least one second printing cylinder following saidtransfer cylinder for selective one-side or twoside printing of sheets,said last mentioned means including means on said transfer cylinder forselectively grasping either the leading edge of a sheet for one-sideprinting or the trailing edge of a sheet for reversible feeding and thustwo-side printing, arc-shaped plate means constituting a limitedperipheral region of said transfer cylinder and adapted to contact asheet, printed on said first printing cylinder and handled thereafterwithout two-side printing by normal transfer of the sheet to said secondprinting cylinder, selectively actuatable and rever sible means forwithdrawing said arc-shaped plate means into said transfer cylinder tocarry a sheets, reversed after printing on said first printing cylinder,to said second printing cylinder and into contact therewith withoutcreasing of the sheet.

2. Sheet transfer cylinder according to claim 1, wherein said means forwithdrawing said arc-sha ed plate means includes a parallel rockerlinkage disposed in he sheet transfer cylinder and carrying the platemeans.

3. Sheet transfer cylinder according to claim 2 also including cam meansin the sheet transfer cylinder for controlling said parallel rockerlinkage.

4. Sheet transfer cylinder according to claim 1 also including means forselectively locking and unlocking said means for withdrawing thearc-shaped plate means, in the position wherein the plate means iswithdrawn into the transfer cylinder.

1. A printing machine comprising a sheet transfer cylinder, meansincluding at least one first printing cylinder ahead of said transfercylinder and at least one second printing cylinder following saidtransfer cylinder for selective one-side or twoside printing of sheets,said last mentioned means including means on said transfer cylinder forselectively grasping either the leading edge of a sheet for one-sideprinting or the trailing edge of a sheet for reversible feeding and thustwo-side printing, arc-shaped plate means constituting a limitedperipheral region of said transfer cylinder and adapted to contact asheet, printed on said first printing cylinder and handled thereafterwithout two-side printing by normal transfer of the sheet to said secondprinting cylinder, selectively actuatable and reversible means forwithdrawing said arc-shaped plate means into said transfer cylinder tocarry a sheets, reversed after printing on said first printing cylinder,to said second printing cylinder and into contact therewith withoutcreasing of the sheet.
 2. Sheet transfer cylinder according to claim 1,wherein said means for withdrawing said arc-shaped plate means includesa parallel rocker linkage disposed in the sheet transfer cylinder andcarrying the plate means.
 3. Sheet transfer cylinder according to claim2 also including cam means in the sheet transfer cylinder forcontrolling said parallel rocker linkage.
 4. Sheet transfer cylinderaccording to claim 1 also including means for selectively locking andunlocking said means for withdrawing the arc-shaped plate means, in theposition wherein the plate means is withdrawn into the transfercylinder.